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From:   Yuntao Wang <ytcoode@gmail.com>
To:     andrii.nakryiko@gmail.com
Cc:     andrii@kernel.org, ast@kernel.org, bpf@vger.kernel.org,
        daniel@iogearbox.net, john.fastabend@gmail.com, kafai@fb.com,
        kpsingh@kernel.org, linux-kernel@vger.kernel.org,
        netdev@vger.kernel.org, songliubraving@fb.com, toke@redhat.com,
        yhs@fb.com, ytcoode@gmail.com
Subject: [PATCH bpf-next v3] libbpf: Don't return -EINVAL if hdr_len < offsetofend(core_relo_len)
Date:   Mon,  4 Apr 2022 08:53:20 +0800
Message-Id: <20220404005320.1723055-1-ytcoode@gmail.com>
In-Reply-To: <CAEf4Bzbi1E_-yojgJQevM1rdhXF4EzU4dgPsGDT7F5uuDPOE7Q@mail.gmail.com>
References: <CAEf4Bzbi1E_-yojgJQevM1rdhXF4EzU4dgPsGDT7F5uuDPOE7Q@mail.gmail.com>
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Since core relos is an optional part of the .BTF.ext ELF section, we should
skip parsing it instead of returning -EINVAL if header size is less than
offsetofend(struct btf_ext_header, core_relo_len).

Signed-off-by: Yuntao Wang <ytcoode@gmail.com>
---
v1 -> v2: skip core relos if hdr_len < offsetofend(core_relo_len)
v2 -> v3: fix comment style

 tools/lib/bpf/btf.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c
index 1383e26c5d1f..d124e9e533f0 100644
--- a/tools/lib/bpf/btf.c
+++ b/tools/lib/bpf/btf.c
@@ -2826,10 +2826,8 @@ struct btf_ext *btf_ext__new(const __u8 *data, __u32 size)
 	if (err)
 		goto done;
 
-	if (btf_ext->hdr->hdr_len < offsetofend(struct btf_ext_header, core_relo_len)) {
-		err = -EINVAL;
-		goto done;
-	}
+	if (btf_ext->hdr->hdr_len < offsetofend(struct btf_ext_header, core_relo_len))
+		goto done; /* skip core relos parsing */
 
 	err = btf_ext_setup_core_relos(btf_ext);
 	if (err)
-- 
2.35.1